First time I've heard of them. I like the concept but 5$ a month for only 300 search makes me think that you'd still need another search engine on the side, or pay for the more expensive plan.
My family was looking for a specific manual and couldn't find it on Google, the only search engine they know about. It was one of the first results on DDG.
I'm using DDG for a while now and I'm happy with it overall.
Yes, it looks beautiful.